Chevy Tri-Five Suspension Bolt-ons - How It Works

Leading suspension manufacturers explain how to take the handling of Tri-Five Chevys to the next level with a few simple bolt-ons

Tri-Five Chevys are for old guys who are content with 283s and Powerglides. At least that’s what the typical 40-something muscle car enthusiast thinks. Perhaps the high demand and prices of Camaros, Novas, and Chevelles have something to do with it, but that stereotype no longer holds true these days. There seems to be a resurgence in popularity of Tri-Fives as of late, and people aren’t building them like before. The days of puny Mouse motors in stock restoration are long gone, and the new crop of Tri-Fives sport LS-series small-blocks, overdrive transmissions, big rollers, and mean stances.

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Although they look the part of a corner-hugging Pro Touring machine, can they actually walk the walk? The answer is an emphatic yes, and to get details on how to make it happen, we sought the expertise of some of the biggest names in Tri-Five suspension hardware. Our panel includes Craig Morrison of Art Morrison Enterprises, Aaron Strietzel of Classic Performance Parts, Doug Nordin of Global West, and John Hotchkis of Hotchkis Performance. Although we covered aftermarket Tri-Five frames in great detail last month, we wanted to focus on budget-oriented bolt-on suspension upgrades this time around. If there’s anything to be learned from this, it’s that the products are available to build a comfortable cruiser to an all-out performer; there’s plenty to talk about, so let’s get started.

Handling Potential

Craig Morrison: Many hot rodders have proven that the average ’64-72 muscle car can be built to handle very well, but Tri-Five Chevys don’t get much street cred in that regard. Art Morrison Enterprises has been involved with some very impressive Tri-Five builds that have performed quite well in instrumented testing. We built a ’55 Chevy project car named GT55 to showcase our Tri-Five hardware in 2003. The car was fitted with AME suspension components, a Bill Mitchell 530hp small-block, and a Tremec T56 six-speed transmission. After it was completed, we drove it from our facility in Tacoma, Washington, to California Speedway for several rounds of instrumented testing. On BFGoodrich street tires, the car produced some amazing numbers. It pulled 0.94 g on the skidpad, ran the quarter-mile in 12.6 seconds at 116 mph, stopped from 60 mph in 132 feet, and went through a tight slalom course at 48.37 mph. At the time, the most comparable new car to these numbers was a 575M Ferrari. It’s not too often you can compare a Ferrari GT car and a ’55 Chevrolet!

Aaron Strietzel: These cars are usually built as cruisers, and there are many easy bolt-on suspension components available to dramatically improve their street manners. The good news is these cars already have a decent suspension to being with. If you’re starting out with a bone-stock Tri-Five, one of Classic Performance Parts’ frontend rebuild kits is a great place to start. They include a new set of springs, three-way adjustable shocks, and our Polyplus performance graphite control arm bushings, bumpstops, and strut rod bushings. Other components in the kit include ball joints, inner and outer tie-rod ends, and a new idler arm. You take things one step further with a set of our sway bars, control arms, and a 500-series steering box. These simple upgrades will make a Tri-Five handle like a modern daily driver instead of a 50-year-old car, especially if you already have bigger wheels and tires.

John Hotchkis: From a handling perspective, the biggest drawback of the Tri-Five Chevy is that it’s relatively heavy and very tall. That creates a lot of leverage from the glass and roof as the car rolls through a corner. Consequently, one of the worst things you can do is put bigger wheels and tires on a stock suspension car. That puts more stress on the car and makes it roll even more. Even so, you can still make a Tri-Five handle very well, and one of the most affordable and effective modifications you can make is installing a set of sway bars. Combined with sticky tires, our sway bars offer a huge improvement in handling, and Tri-Fives make much better cruisers than first-gen Camaros.

Doug Nordin: Camaros, Novas, and Chevelles are very popular amongst the Pro Touring crowd but with the right parts you can get a Tri-Five to handle just as well. Not a lot of people actually autocross their cars, so some basic upgrades is all it takes to vastly improve a car’s street handling. At Global West, our parts are designed for people who want bolt-on simplicity using the stock frame. We offer tubular upper and lower control arms, sway bars, coil springs, leaf springs, and steering boxes. Together, these parts substantially improve driveability and cornering. For the best bang for the buck, upgrading the front control arms is where it’s at. They add much more caster for improved stability and corner entry, and change the camber curve for improved grip. Next on the list should be an upgraded steering box. We offer a Borgeson 12.0:1 unit that has much better steering feel and a quicker ratio than stock.

Weak Links

Craig Morrison: The factory Tri-Five Chevy suspension design looks good on paper, but it certainly has its limitations. While they utilize a full frame with a double A-arm front suspension design, the geometry is all wrong for modern tires and performance driving. There is positive camber and toe-out, which leads to lots of understeer. In the back, it is a simple parallel leaf design that does a good job of holding the car up and that’s about it. The biggest thing to keep in mind is that the Tri-Five suspension was designed for bias-ply tires, not modern radials. The additional grip of modern tires puts more load through the suspension, and makes its shortcomings even worse. An aftermarket frame offers the ultimate in ride and handling performance for a Tri-Five, but there are many more affordable options. Aftermarket control arms, coilover kits, and sway bars are just some of the hardware that’s available. AME offers a center X kit that strengthens the center portion of the chassis and many different options of grafting a suspension in out back. From individual components to a full rear subframe, it all depends on your budget, fabrication skill set, what you want to do with the car, and how you are going to drive it.

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Sway Bars

John Hotchkis: For people who don’t want to spend the money on an aftermarket frame, a sway bar package offers a great dollar-per-dollar performance value. Hotchkis Performance offers a front and rear sway bar package that makes a huge difference in car control and comfort. The stock Tri-Five suspension has no rear sway bar at all, so adding one dramatically improves handling. Our comprehensive kit works great with stock frames, and features a 13/8-inch sway bar that’s 60 percent stiffer than stock as well as an adjustable 1-inch rear bar. To tailor rear roll stiffness to a wide range of tire sizes, our rear bar has two sets of adjustment holes that offer both 309 and 480 lb/in of stiffness. Furthermore, our bars are hollow for excellent twist resistance and reduced mass. Compared to a solid bar, our hollow units are about 10 pounds lighter. Each sway bar kit includes laser-cut mounts, stainless U-bolts, polyurethane bushings, and a black powdercoated finish.

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Through many hours of testing, we were able to increase the front roll stiffness as aggressively as necessary while still keeping a comfortable ride and a fair amount of compliance. This greatly improves turn-in ability while reducing body roll. Then we matched the front bar up with the rear bar that had just enough roll stiffness to achieve neutral handling balance. The adjustability built into the rear bar allows optimizing handling balance to get the most out of all four contact patches. Overall, our Tri-Five sway bars make a car more responsive, and they are very easy to install in a single afternoon.

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Body Mounts

Craig Morrison: Body mounts are a point where the chassis and body can flex in a full-frame car. Depending on the height of the body mount, this can become a point to look at for improvement. The problem can become worse with older, worn-out body mounts. Thankfully, the OE body mount design isn’t that tall on a Tri-Five, so the replacement rubber mounts work just fine. There are companies out there that do offer a more rigid polyurethane body mount that helps unitize the chassis and body just a bit better. While we do have aluminum body mounts for some of our other applications where we have decreased the distance from chassis to body, or are looking to increase the rigidity in body mounting, we felt that it wouldn’t be a significant area for improvement.

Control Arms

Aaron Strietzel: If you’ve already rebuilt the frontend of your Tri-Five, the next logical upgrade is a set of tubular control arms. CPP’s control arms are built from 1.25 inches with thick 1.5-inch pivot barrels to eliminate distortion. Their billet 4140 cross-shafts are zinc, and designed to carry both fore-and-aft loads. One of the biggest benefits of these control arms is that they add 5 degrees of positive caster for improved straight-line stability. Additionally, they have a revised camber curve that keeps a larger contact patch on the ground as the suspension compresses.

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Springs

Craig Morrison: A set of 60-year-old springs aren’t going to cut it in a performance car, and AME offers both coil springs and air springs for Tri-Five Chevys. With coil springs, you usually know exactly what the spring rate is, and most have a linear rate. During the setup of the chassis, you can set ride height or scale the car, but that’s about it. You might have to readjust the car setup when the springs settle in or if you are fine-tuning for track day events. If your vehicle load varies quite a bit, then there will be some sag. With air springs, you can instantly adjust this on the fly, and you can also get to shows and dump the air out to get your vehicle to sit very low. Air springs are a progressive rate, so they can be trickier to fine-tune, and air springs with integrated shocks generally have a reduced amount of shock travel. Furthermore, an air spring system with the tanks, solenoids, and control unit can often be many times more expensive than a quality set of coilovers.

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Rear Clips

Craig Morrison: The factory Tri-Five leaf-spring rear suspension isn’t well suited for high-performance handling. AME sells both a complete rear clip assembly with a triangulated four-bar suspension as well as and the individual components necessary to graft the suspension pieces onto the chassis. The biggest improvements of our four-bar setup over the stock leaf springs are the stability of the roll center and the suspension’s ability to plant the tire and accelerate quickly. We also offer Strange Engineering adjustable coilovers with this package, so a customer can fine-tune the level of performance desired. Also, we have just recently gone to an adjustable sway bar that will give the customer another level of adjustment to dial their car in for their style of driving. The ride quality is going to be dramatically improved as well. By going to the triangulated four-bar, you eliminate the inter-leaf friction that affects the ride quality. This increases lateral stability since there is no track locator on the original setup.

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Steering

Aaron Strietzel: One of the most popular upgrades for Tri-Five Chevys is our 500-series steering box. Suspension upgrades won’t do much good if a car doesn’t go where you point it. The 500-series box features a 14.0:1 ratio, and a unique one-piece housing. It’s a direct replacement for the factory 605-style box, and offers vastly improved steering feel and response. Included in the kit are a power steering hose and a mounting bracket. Compared to stock, the 500-series box eliminates the sloppy feeling of a factory box, and it makes a Tri-Five drive like modern car.

Craig Morrison: The factory Tri-Five steering box is designed more for cruising than for handling, and chances are the stock steering links have seen better days. We offer an AGR power rack-and-pinion unit on both our bikini clip subframe kit and our full-frame chassis. They’re available in both 15.0:1 and 20.0:1 ratios. From a packaging standpoint, the rack allows more room for a set of long-tube headers. With less moving parts and pivots than a steering box, a rack will have less play and greater precision. Its lighter weight also helps remove excess pounds off of the frontend.

Fighting Deflection

Doug Nordin: As full-frame cars, Tri-Five Chevys might be a little stiffer than unibody cars like first-gen Camaros, but they still flex quite a bit. Sometimes you have to reinforce the center of the frame in full-frame cars. When designing suspension components, the hard part is reducing deflection while maintaining ride quality. Reinforcing every part of a chassis then using rubber bushings isn’t a good idea. The same goes for the body mounts. To combat deflection, Global West uses our Del-a-lum bushings that are much stronger than a conventional bushing. They actually work more like a bearing. Del-a-lum bushings feature a hard plastic from DuPont that acts as a bearing surface and slides in an aluminum housing. They also have grease grooves for lubrication. This design allows for straight up and down movement with no fore-and-aft deflection, and reduces wear as well. Our bushings have been proven to last for 300,000 miles.

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Front Clips

Craig Morrison: For hot rodders who want a dramatic improvement in handling without the expense of a full-frame kit, AME offers front bikini clips. The installation process is more involved than a typical bolt-on, but the great advantage is that all of the suspension geometry is correct and squared. Our clips are built from 2x4-inch rectangular tubing, and can be fitted with our tubular control arms, coilovers, sway bars, spindles, and steering rack. The biggest issue with the installation of our bikini clip is to make sure that it is square with the rest of the chassis before welding it in place. For a first-time fabricator, this would be a big job, but for somebody who has experience with fabrication and has built a few cars, this shouldn’t be a monumental job. There is definitely a point of no return when you start cutting your OE chassis apart, but as long as you go by the old rule of measuring twice and cutting once, you should be just fine.

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